CVE-2026-54538 xrdp: Pre-auth infinite loop via totalLength=0 in TS_SHARECONTROLHEADER
Unauthenticated attackers can cause a denial of service in xrdp by sending crafted packets that trigger an infinite loop, exhausting CPU resources.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-54538?
CVE-2026-54538 is a high-severity denial of service vulnerability in neutrinolabs xrdp, published on 20 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
xrdp is an open source RDP server. In versions 0.10.6 and prior, a n issue was discovered where the software fails to properly validate the totalLength field within the RDP protocol control header during packet reception. An unauthenticated remote attacker can exploit this vulnerability by sending a specially crafted packet that forces the xrdp process or thread into an infinite, CPU-bound loop. Because the internal pointer fails to advance and the deadlock prevention mechanism is bypassed for specific protocol data unit types, the process consumes excessive CPU resources indefinitely. This can render the xrdp service unavailable and potentially lead to system-wide resource exhaustion if multiple malicious connections are established. This issue has been fixed in version 0.10.6.1.
Weakness: CWE-835
Which versions are affected by CVE-2026-54538?
It affects 1 product.
Products include Neutrinolabs Xrdp.
How do I fix CVE-2026-54538?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-54538 being exploited?
There is no known exploitation of CVE-2026-54538 in the wild and no public exploit code.
Other vulnerabilities in neutrinolabs xrdp
- CVE-2026-41252 xrdp: lib_palette_update Heap Buffer Overflow & RCE
- CVE-2026-32105 xrdp: RDP MAC signature (dataSignature) never verified on receive — integrity bypass in non-TLS mode
- CVE-2026-44178 xrdp: Channel Data Forwarding Fixed-Size Buffer Overflow
- CVE-2026-32107 xrdp: Fail-open privilege drop in sesexec — child processes may execute as root if setuid fails
- CVE-2026-33689 xrdp: Pre-authentication out-of-bounds reads in channel parsers
Sources
Also known as DEBIAN-CVE-2026-54538, GHSA-9j3q-9mvw-qv7j, UBUNTU-CVE-2026-54538.